Wireless communication systems are widely deployed for providing various telecommunication services such as telephony, video, data, messaging, broadcasts and so on. Typical wireless communication systems employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (for example, bandwidth, transmit power and so on). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE).
The 3GPP defines a closed subscriber group (CSG), which identifies subscribers of an operator who are permitted to access a cell (CSG) of a Public Land Mobile Network (PLMN) but which have restricted access (CSG cells). A CSG cell is accessible by the members of the CSG using a CSG identity (CSG ID). In automatic mode of CSG selection, the Access Stratum (AS) layer in the User Equipment (UE) utilizes the White List (combination of Operator CSG list and Allowed CSG list) to reselect or handover to the CSG cell.
The Allowed CSG List can be modified by the operator, or the UE or both. Further, the UE maintains an operator controlled list of allowed CSG identities (Operator CSG list), which are modified only by the operator. The UE uses the Allowed CSG List and Operator CSG list along with the CSG ID broadcast by the CSG for CSG cell selection and reselection.
In manual mode of CSG selection, the UE enables a user to select a CSG ID. For the manual CSG selection, the user shall be able to request the UE to perform a scan for available CSGs. When such request is received from the user, the UE shall perform a scan of available CSGs, CSG identities and their Home Node B (HNB) Names. Further, the available CSGs are displayed to user based on configuration by a Home Public Land Mobile Network (HPLMN) on the Universal Integrated Circuit Card (UICC). Upon manually selecting the CSG cell, the UE behavior is differentiated based on whether the selected CSG belongs to the Registered PLMN (RPLMN) or not.
In the existing system, if the PLMN of the selected CSG is different than the RPLMN, then the UE saves the “current PLMN selection mode” and a duplicate value of RPLMN into a non-volatile memory. Further, upon successful registration on the selected CSG cell, the RPLMN is not updated with that of the selected PLMN.